fs/qnx4/inode.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * QNX4 file system, Linux implementation.
   4  *
   5  * Version : 0.2.1
   6  *
   7  * Using parts of the xiafs filesystem.
   8  *
   9  * History :
  10  *
  11  * 01-06-1998 by Richard Frowijn : first release.
  12  * 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.
  13  * 30-06-1998 by Frank Denis : first step to write inodes.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/highuid.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/writeback.h>
  23 #include <linux/statfs.h>
  24 #include <linux/fs_context.h>
  25 #include "qnx4.h"
  26
  27 #define QNX4_VERSION  4
  28 #define QNX4_BMNAME   ".bitmap"
  29
  30 static const struct super_operations qnx4_sops;
  31
  32 static struct inode *qnx4_alloc_inode(struct super_block *sb);
  33 static void qnx4_free_inode(struct inode *inode);
  34 static int qnx4_statfs(struct dentry *, struct kstatfs *);
  35 static int qnx4_get_tree(struct fs_context *fc);
  36
  37 static const struct super_operations qnx4_sops =
  38 {
  39         .alloc_inode    = qnx4_alloc_inode,
  40         .free_inode     = qnx4_free_inode,
  41         .statfs         = qnx4_statfs,
  42 };
  43
  44 static int qnx4_reconfigure(struct fs_context *fc)
  45 {
  46         struct super_block *sb = fc->root->d_sb;
  47         struct qnx4_sb_info *qs;
  48
  49         sync_filesystem(sb);
  50         qs = qnx4_sb(sb);
  51         qs->Version = QNX4_VERSION;
  52         fc->sb_flags |= SB_RDONLY;
  53         return 0;
  54 }
  55
  56 static const struct fs_context_operations qnx4_context_opts = {
  57         .get_tree       = qnx4_get_tree,
  58         .reconfigure    = qnx4_reconfigure,
  59 };
  60
  61 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
  62 {
  63         unsigned long phys;
  64
  65         QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
  66
  67         phys = qnx4_block_map( inode, iblock );
  68         if ( phys ) {
  69                 // logical block is before EOF
  70                 map_bh(bh, inode->i_sb, phys);
  71         }
  72         return 0;
  73 }
  74
  75 static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
  76 {
  77         u32 size = le32_to_cpu(extent->xtnt_size);
  78         if (*offset < size)
  79                 return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
  80         *offset -= size;
  81         return 0;
  82 }
  83
  84 unsigned long qnx4_block_map( struct inode *inode, long iblock )
  85 {
  86         int ix;
  87         long i_xblk;
  88         struct buffer_head *bh = NULL;
  89         struct qnx4_xblk *xblk = NULL;
  90         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
  91         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
  92         u32 offset = iblock;
  93         u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
  94
  95         if (block) {
  96                 // iblock is in the first extent. This is easy.
  97         } else {
  98                 // iblock is beyond first extent. We have to follow the extent chain.
  99                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
 100                 ix = 0;
 101                 while ( --nxtnt > 0 ) {
 102                         if ( ix == 0 ) {
 103                                 // read next xtnt block.
 104                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
 105                                 if ( !bh ) {
 106                                         QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
 107                                         return -EIO;
 108                                 }
 109                                 xblk = (struct qnx4_xblk*)bh->b_data;
 110                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
 111                                         QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
 112                                         return -EIO;
 113                                 }
 114                         }
 115                         block = try_extent(&xblk->xblk_xtnts[ix], &offset);
 116                         if (block) {
 117                                 // got it!
 118                                 break;
 119                         }
 120                         if ( ++ix >= xblk->xblk_num_xtnts ) {
 121                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
 122                                 ix = 0;
 123                                 brelse( bh );
 124                                 bh = NULL;
 125                         }
 126                 }
 127                 if ( bh )
 128                         brelse( bh );
 129         }
 130
 131         QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
 132         return block;
 133 }
 134
 135 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
 136 {
 137         struct super_block *sb = dentry->d_sb;
 138         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 139
 140         buf->f_type    = sb->s_magic;
 141         buf->f_bsize   = sb->s_blocksize;
 142         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
 143         buf->f_bfree   = qnx4_count_free_blocks(sb);
 144         buf->f_bavail  = buf->f_bfree;
 145         buf->f_namelen = QNX4_NAME_MAX;
 146         buf->f_fsid    = u64_to_fsid(id);
 147
 148         return 0;
 149 }
 150
 151 /*
 152  * Check the root directory of the filesystem to make sure
 153  * it really _is_ a qnx4 filesystem, and to check the size
 154  * of the directory entry.
 155  */
 156 static const char *qnx4_checkroot(struct super_block *sb,
 157                                   struct qnx4_super_block *s)
 158 {
 159         struct buffer_head *bh;
 160         struct qnx4_inode_entry *rootdir;
 161         int rd, rl;
 162         int i, j;
 163
 164         if (s->RootDir.di_fname[0] != '/' || s->RootDir.di_fname[1] != '\0')
 165                 return "no qnx4 filesystem (no root dir).";
 166         QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
 167         rd = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_blk) - 1;
 168         rl = le32_to_cpu(s->RootDir.di_first_xtnt.xtnt_size);
 169         for (j = 0; j < rl; j++) {
 170                 bh = sb_bread(sb, rd + j);      /* root dir, first block */
 171                 if (bh == NULL)
 172                         return "unable to read root entry.";
 173                 rootdir = (struct qnx4_inode_entry *) bh->b_data;
 174                 for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
 175                         QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
 176                         if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
 177                                 continue;
 178                         qnx4_sb(sb)->BitMap = kmemdup(rootdir,
 179                                                       sizeof(struct qnx4_inode_entry),
 180                                                       GFP_KERNEL);
 181                         brelse(bh);
 182                         if (!qnx4_sb(sb)->BitMap)
 183                                 return "not enough memory for bitmap inode";
 184                         /* keep bitmap inode known */
 185                         return NULL;
 186                 }
 187                 brelse(bh);
 188         }
 189         return "bitmap file not found.";
 190 }
 191
 192 static int qnx4_fill_super(struct super_block *s, struct fs_context *fc)
 193 {
 194         struct buffer_head *bh;
 195         struct inode *root;
 196         const char *errmsg;
 197         struct qnx4_sb_info *qs;
 198         int silent = fc->sb_flags & SB_SILENT;
 199
 200         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 201         if (!qs)
 202                 return -ENOMEM;
 203         s->s_fs_info = qs;
 204
 205         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 206
 207         s->s_op = &qnx4_sops;
 208         s->s_magic = QNX4_SUPER_MAGIC;
 209         s->s_flags |= SB_RDONLY;        /* Yup, read-only yet */
 210         s->s_time_min = 0;
 211         s->s_time_max = U32_MAX;
 212
 213         /* Check the superblock signature. Since the qnx4 code is
 214            dangerous, we should leave as quickly as possible
 215            if we don't belong here... */
 216         bh = sb_bread(s, 1);
 217         if (!bh) {
 218                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
 219                 return -EINVAL;
 220         }
 221
 222         /* check before allocating dentries, inodes, .. */
 223         errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
 224         brelse(bh);
 225         if (errmsg != NULL) {
 226                 if (!silent)
 227                         printk(KERN_ERR "qnx4: %s\n", errmsg);
 228                 return -EINVAL;
 229         }
 230
 231         /* does root not have inode number QNX4_ROOT_INO ?? */
 232         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 233         if (IS_ERR(root)) {
 234                 printk(KERN_ERR "qnx4: get inode failed\n");
 235                 return PTR_ERR(root);
 236         }
 237
 238         s->s_root = d_make_root(root);
 239         if (s->s_root == NULL)
 240                 return -ENOMEM;
 241
 242         return 0;
 243 }
 244
 245 static int qnx4_get_tree(struct fs_context *fc)
 246 {
 247         return get_tree_bdev(fc, qnx4_fill_super);
 248 }
 249
 250 static int qnx4_init_fs_context(struct fs_context *fc)
 251 {
 252         fc->ops = &qnx4_context_opts;
 253
 254         return 0;
 255 }
 256
 257 static void qnx4_kill_sb(struct super_block *sb)
 258 {
 259         struct qnx4_sb_info *qs = qnx4_sb(sb);
 260         kill_block_super(sb);
 261         if (qs) {
 262                 kfree(qs->BitMap);
 263                 kfree(qs);
 264         }
 265 }
 266
 267 static int qnx4_read_folio(struct file *file, struct folio *folio)
 268 {
 269         return block_read_full_folio(folio, qnx4_get_block);
 270 }
 271
 272 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 273 {
 274         return generic_block_bmap(mapping,block,qnx4_get_block);
 275 }
 276
 277 static const struct address_space_operations qnx4_aops = {
 278         .read_folio     = qnx4_read_folio,
 279         .bmap           = qnx4_bmap
 280 };
 281
 282 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 283 {
 284         struct buffer_head *bh;
 285         struct qnx4_inode_entry *raw_inode;
 286         int block;
 287         struct qnx4_inode_entry *qnx4_inode;
 288         struct inode *inode;
 289
 290         inode = iget_locked(sb, ino);
 291         if (!inode)
 292                 return ERR_PTR(-ENOMEM);
 293         if (!(inode->i_state & I_NEW))
 294                 return inode;
 295
 296         qnx4_inode = qnx4_raw_inode(inode);
 297         inode->i_mode = 0;
 298
 299         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 300         if (!ino) {
 301                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 302                                 "out of range\n",
 303                        sb->s_id, ino);
 304                 iget_failed(inode);
 305                 return ERR_PTR(-EIO);
 306         }
 307         block = ino / QNX4_INODES_PER_BLOCK;
 308
 309         if (!(bh = sb_bread(sb, block))) {
 310                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 311                        "%s\n", sb->s_id);
 312                 iget_failed(inode);
 313                 return ERR_PTR(-EIO);
 314         }
 315         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 316             (ino % QNX4_INODES_PER_BLOCK);
 317
 318         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 319         i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
 320         i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
 321         set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
 322         inode->i_size    = le32_to_cpu(raw_inode->di_size);
 323         inode_set_mtime(inode, le32_to_cpu(raw_inode->di_mtime), 0);
 324         inode_set_atime(inode, le32_to_cpu(raw_inode->di_atime), 0);
 325         inode_set_ctime(inode, le32_to_cpu(raw_inode->di_ctime), 0);
 326         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 327
 328         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 329         if (S_ISREG(inode->i_mode)) {
 330                 inode->i_fop = &generic_ro_fops;
 331                 inode->i_mapping->a_ops = &qnx4_aops;
 332                 qnx4_i(inode)->mmu_private = inode->i_size;
 333         } else if (S_ISDIR(inode->i_mode)) {
 334                 inode->i_op = &qnx4_dir_inode_operations;
 335                 inode->i_fop = &qnx4_dir_operations;
 336         } else if (S_ISLNK(inode->i_mode)) {
 337                 inode->i_op = &page_symlink_inode_operations;
 338                 inode_nohighmem(inode);
 339                 inode->i_mapping->a_ops = &qnx4_aops;
 340                 qnx4_i(inode)->mmu_private = inode->i_size;
 341         } else {
 342                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 343                         ino, sb->s_id);
 344                 iget_failed(inode);
 345                 brelse(bh);
 346                 return ERR_PTR(-EIO);
 347         }
 348         brelse(bh);
 349         unlock_new_inode(inode);
 350         return inode;
 351 }
 352
 353 static struct kmem_cache *qnx4_inode_cachep;
 354
 355 static struct inode *qnx4_alloc_inode(struct super_block *sb)
 356 {
 357         struct qnx4_inode_info *ei;
 358         ei = alloc_inode_sb(sb, qnx4_inode_cachep, GFP_KERNEL);
 359         if (!ei)
 360                 return NULL;
 361         return &ei->vfs_inode;
 362 }
 363
 364 static void qnx4_free_inode(struct inode *inode)
 365 {
 366         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 367 }
 368
 369 static void init_once(void *foo)
 370 {
 371         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 372
 373         inode_init_once(&ei->vfs_inode);
 374 }
 375
 376 static int init_inodecache(void)
 377 {
 378         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 379                                              sizeof(struct qnx4_inode_info),
 380                                              0, (SLAB_RECLAIM_ACCOUNT|
 381                                                 SLAB_ACCOUNT),
 382                                              init_once);
 383         if (qnx4_inode_cachep == NULL)
 384                 return -ENOMEM;
 385         return 0;
 386 }
 387
 388 static void destroy_inodecache(void)
 389 {
 390         /*
 391          * Make sure all delayed rcu free inodes are flushed before we
 392          * destroy cache.
 393          */
 394         rcu_barrier();
 395         kmem_cache_destroy(qnx4_inode_cachep);
 396 }
 397
 398 static struct file_system_type qnx4_fs_type = {
 399         .owner                  = THIS_MODULE,
 400         .name                   = "qnx4",
 401         .kill_sb                = qnx4_kill_sb,
 402         .fs_flags               = FS_REQUIRES_DEV,
 403         .init_fs_context        = qnx4_init_fs_context,
 404 };
 405 MODULE_ALIAS_FS("qnx4");
 406
 407 static int __init init_qnx4_fs(void)
 408 {
 409         int err;
 410
 411         err = init_inodecache();
 412         if (err)
 413                 return err;
 414
 415         err = register_filesystem(&qnx4_fs_type);
 416         if (err) {
 417                 destroy_inodecache();
 418                 return err;
 419         }
 420
 421         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 422         return 0;
 423 }
 424
 425 static void __exit exit_qnx4_fs(void)
 426 {
 427         unregister_filesystem(&qnx4_fs_type);
 428         destroy_inodecache();
 429 }
 430
 431 module_init(init_qnx4_fs)
 432 module_exit(exit_qnx4_fs)
 433 MODULE_DESCRIPTION("QNX4 file system");
 434 MODULE_LICENSE("GPL");
 435